21. Data communication

Figure 1. Example of a connection of routers for a computer network

1. General Information

Due to nature of electrical signal property, signals transmitted on a line would spread to another line if they’re connected. This was the issue of many signal data spreading around the world even though, they’re not intended to.

2. Solution

As shown in figure 1, this is an example of a computer network connection for many LAN or computers to exchange data.

In order to avoid data sending to wrong router(s) and relay around the world for no reason, each router must have separate and isolated connector to another router. Therefore signal data sending to another router would not be spread to another router that it’s also connected to. For example, Router A has 2 separate connectors; one for connection to Router B and the other one for Router C.

If Comp 1 is sending an email to or communicating with Comp 2, Router A would not relay data to its surrounding routers, i.e. Router B and Router C. The communication is internally handled within the LAN of Router A. The network is closed to outside.

If Comp 1 is sending an email to Comp 7,

·        Router A would receive and analyze data for the destination IP (IP packet) from comp 1, i.e. Comp 5’s IP.

·        Router A doesn’t relay data to comp 2, comp 3, or Router C.

·        Router A would relay comp 1’s data to Router B, because it’s based on its routing database. The only path to Comp 7 would be through Router B.

·        Router B received data from Router A for communication between Comp 1 and Comp 7.

·        Router B would analyze the destination IP in the IP packet.

·        Router would only relay that IP packet to Router D, but it wouldn’t broadcast that data to its internal network, i.e. Comp 4, Comp 5, and Comp 6.

·        Network Router D would receive and analyze the IP packet and relay data to Comp 7 as expected. Because a router, e.g. a WiFi router, doesn’t have separate connectors to each computer in its internal network, thus this IP packet would be broadcast within LAN. Comp 7 would pick it up as expected.

3. Routing database

Network planners must be able to plan in advance the path an IP packet would go in order to reach its destination based on its destination IP address in its database. For example,

·        Router A’s routing database

Source IP (OPC)       Destination IP (DPC)          Transfer Node

Any                                 87.78.25.150                        32.45.96.25

·        Router B’s routing database

Source IP (OPC)       Destination IP (DPC)          Transfer Node

Any                                25.68.12.121                         27.38.123.36

·        Router C’s routing database

Source IP (OPC)       Destination IP (DPC)          Transfer Node

Any                                32.45.96.25                           27.38.123.36

Any                                87.78.25.150                         27.38.123.36

The IP of each computer is recognized by other external routers via the IP address of its router.

The originating (source) IP address is left blank to accept forwarding any IP packets passing through it to the destination. However, a router could restrict its functionality to pass data by specifying “allowable” originated IP addresses.

This methodology is like hardcoded database for routing IP packets. It was intended for satellite networks as there are not many satellites in orbits. New satellites are launched into orbits or defunct less frequently as compared to new ISP and deprecated ISP on earth.

This methodology could be used for international exchanges (computer or telephony), if each country is assigned a unique set of IP addresses (or country code), e.g. identified by the first 6 digits of an IP address. Furthermore, each state would control their assigned IP to each ISP or company within their border (phone’s area code). The issue was that updating IP addresses in database would be labor intensive for computer (or telephony) networks as compared to satellite networks.

The telephony network messed up its allocation of area codes and NPA codes, thus it’s hard to deliver a phone call to a nearest local phone operator based on dialed area code and NPA code. If IP address was organized by areas properly, telephone operators could map a dialed phone number (DPC) into a destination IP address and deliver to its nearest destination for applications such as calling a toll free number and dispatching automatically to nearest local operator.  Since 2.5G or GPRS standard, each phone number was also associated to an IP address for data communication, thus mapping an IP address to a phone number or vice versa is possible.